Locking between levels of a multi-level helix device

ABSTRACT

An inter-level locking mechanism of a multi- level medical device is disclosed. The locking mechanism includes (a) an elongated element ( 100 ) having a plurality of flexing regions, wherein the elongated element assumes a straightened configuration for introduction into the body, and wherein the elongated element assumes a closed helix configuration with a first portion of the elongated element coming in overlapping contact with a second portion of the elongated element in the closed helix configuration, and (b) at least one locking element deployable so as to interconnect the first and second portions of the elongated element so as to tighten together the overlapping portions of the elongated element, thereby stabilizing the closed helix configuration.

FIELD OF THE INVENTION

The invention relates generally to medical devices, and more particularly to a locking mechanism between levels of a medical device with a multi-level helix configuration.

BACKGROUND OF THE INVENTION

A device for introduction into a body in a straight configuration and assuming within the body a predefined curved configuration has been disclosed in international patent application WO 2006/072941. The device included an elongated element formed from a number of segments interconnected so as to form effective hinges therebetween. The elongated element is introduced in a straight configuration within a conduit and assumes a curved configuration when deployed. The device curved configuration might be an in-plane one level closed loop configuration implant or an out-of-plane closed helix with two or more helix levels. Both devices, and more severely the out-of-plane closed helix device, are required to maintain their configuration in the patient body under significant deforming forces.

Thus, it would be highly advantageous to provide a locking mechanism between levels of a medical device with a multi-level helix configuration that would stabile and reinforce the multi-level helix devices.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, there is provided an inter-level locking mechanism of a multi-level medical device including (a) an elongated element having a plurality of flexing regions, wherein the elongated element assumes a straightened configuration for introduction into the body, and wherein the elongated element assumes a closed helix configuration with a first portion of the elongated element coming in overlapping contact with a second portion of the elongated element in the closed helix configuration, and (b) at least one locking element deployable so as to interconnect the first and second portions of the elongated element so as to tighten together the overlapping portions of the elongated element, thereby stabilizing the closed helix configuration.

According to a further feature of an embodiment of the present invention, at least one locking element includes a flexible tensioning element anchored to the first portion of the medical device and passing directly between levels of the closed helix configuration so as to tighten together the overlapping portions of the elongated element.

According to a further feature of an embodiment of the present invention, the second portion of the elongated element comes in overlapping contact with a third portion of the elongated element in the closed helix configuration, thereby defining three levels of the closed helix configuration, and wherein at least one locking element additionally engages the third region of the elongated element, thereby tightening together the three levels of the closed helix configuration.

According to a further feature of an embodiment of the present invention, the second portion of the elongated element comes in overlapping contact with a third portion of the elongated element in the closed helix configuration, thereby defining three levels of the closed helix configuration, and wherein the flexible tensioning element additionally engages the third region of the elongated element, thereby tightening together the three levels of the closed helix configuration.

According to a further feature of an embodiment of the present invention, at least part of the elongated element may be provided with protrusions and at least part of the elongated element may be provided with complementary recesses, the protrusions and recesses being configured and deployed such that, when the elongated element assumes the closed helix configuration, the protrusions and complementary recesses inter-engage so as to further stabilize and reinforce the closed helix configuration.

According to a further feature of an embodiment of the present invention, a second locking element locking the element in a second position along the element in addition to the at least distal portion to the proximal portion locking element may be provided.

According to a further feature of an embodiment of the present invention, the elongated element may be formed from a plurality of links interconnected at the plurality of flexing regions.

According to an embodiment of the present invention, there is provided a method for locking a multi-level medical device within a body comprising the steps of: (a) inserting an elongated element having a plurality of flexing regions, wherein the clement assumes a straightened configuration for introduction into the body, and wherein the elongated element assumes a closed helix configuration with a first portion of the elongated element coming in overlapping contact with a second portion of the elongated element in the closed helix configuration when deployed, and (b) deploying a locking element so as to interconnect the first and second portions of the elongated element so as to tighten together the overlapping portions of the elongated element, thereby stabilizing the closed helix configuration.

According to a further feature of an embodiment of the present invention, the locking element includes a flexible tensioning element anchored at the first portion of the elongated element and passing directly between levels of the closed helix configuration so as to tighten together the overlapping portions of the elongated element.

According to a further feature of an embodiment of the present invention, at least part of an upper or lower overlap surface of the elongated element may be provided with protrusions and at least part of an upper or lower overlap surface of the elongated element may be provided with complementary recesses, the protrusions and recesses being configured and deployed such that, when the locking element is deployed, the protrusions and recesses are locked in engagement, thereby further stabilizing the closed helix configuration.

According to a further feature of an embodiment of the present invention, a second locking element, locking between levels of the closed helix configuration in an additional region of overlap, may be deployed.

Additional features and advantages of the invention will become apparent from the following drawings and description.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which like numerals designate corresponding elements or sections throughout.

With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the accompanying drawings:

FIG. 1 illustrates a multi-level medical device in its elongated straightened configuration , according to embodiments of the present invention;

FIG. 2 illustrates the multi-level medical device in its closed helix configuration, according to embodiments of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Certain embodiments of the present invention provide an inter-level locking mechanism of a multi-level medical device, such as a medical tool or an implant, wherein an elongated element having a plurality of flexing regions assumes a straightened configuration for introduction into the body. The elongated element assumes a closed helix configuration with a first portion of the elongated element coming in overlapping contact with a second portion of the elongated element in the closed helix configuration.

Hereinafter the term “first portion” will be used to refer to a portion of the elongated clement which closes into overlapping relation with another part of the elongated element. According to certain preferred implementations, the “first portion” is at or near the tip which is deployed first, referred to also as the “distal” portion. The term “second portion” will be used to refer to a portion of the elongated element upon which the first portion is deployed in overlapping relation when formed into a closed helical structure. The second portion is clearly “proximal” relative to the first portion, but may be at an intermediate position along the elongated element. The term “third portion” will be used to refer to a portion of the elongated element upon which the second portion is deployed in overlapping relation when formed into a closed helical structure. Here too, the third portion is proximal to the second portion, but may be at an intermediate position along the elongated element, where the deployed configuration includes additional turns of the helical structure.

The present invention relates to “multi-level implants”, i.e., implants which have a deployed state in which at least part of the implant is deployed in a second level or layer relative to another part of the implant, making an out-of-plane or three-dimensional (3D) structure. This is in contrast to an “in-plane one level closed loop configuration implant” in which all the elongated element plurality of links are in one plane.

The plurality of flexing regions are slightly inclined upwards out-of-plane relative to an in-plane one level closed loop configuration implant such that the elongated element assumes a closed helix configuration with at least a bottom part of the distal portion of the elongated element coming in contact with an upper part of the elongated element when deployed in its closed helix configuration.

The inter-level locking mechanism includes at least one locking element deployable so as to interconnect the first and second portions of the elongated element so as to tighten together the overlapping portions of the elongated element, thereby stabilizing the closed helix configuration when deployed.

FIG. 1 illustrates a multi-level implant in its elongated straightened configuration, according to embodiments of the present invention. Elongated element 100 assumes a straightened configuration for insertion through into the body with a low cross sectional profile. In certain non-limiting cases, insertion may be performed via a delivery conduit (not shown). Elongated element 100 may be formed from links 120 interconnected at the flexing regions, including distal link 124, mid link 126, second link 130 and proximal link 134. The links may be made of any suitable material. Typically preferred but non-limiting examples include plastic (e.g. PEEK, UHMWPE, etc.), metal (e.g. Titanium, Stainless Steel, etc.), or a combination of metal and plastic. Elongated element 100 may be formed from plurality of links interconnected at the flexing regions. The links described herein above are non limiting examples of such links and furthermore other structures that may be used to form elongated element 100 are within the scope of the present invention. By way of example, the links described herein may be replaced by intrinsic, or integral and/or elastic joints or by any other structures permitting flexion.

The links may be interconnected by effective hinge axes 115 which are slightly inclined out-of-plane relative to the plane of an in-plane one level closed loop configuration implant, resulting in a helix-like deflected configuration when deployed within the body. The effective hinge axes may be formed by conventional hinge mechanisms of any type, by integrally formed hinges or by any other structure which provides well defined flexing properties between adjacent segments of the structure.

According to certain embodiments of the present invention, at least one locking element that includes a flexible tensioning element may be anchored to the first portion of the implant and passing directly between levels of the implant so as to tighten together said overlapping portions of said elongated element into a closed helix configuration when deployed. The locking element may additionally engage a third region of the elongated element, thereby tightening together the three levels of the implant. The locking element may engage any number of regions beyond the third region of the elongated element described herein above, thereby tightening together any number of levels of the multi-level helix device according to embodiments of the present invention.

Elongated element 100 includes a flexible tensioning element 110, typically implemented as either a plastic or metal thread, and a tightener, such as a proximal roller 140 (which may be also typically formed either from plastic or metal. Flexible tensioning element 110 is preferably fixedly attached to distal link 124, or at some other location along the elongated element, and is threaded through at least one additional link, such as mid link 126 and proximal link 134. The other end of the tensioning element may be connected to proximal roller 140. Proximal roller 140 is a non-limiting example of a mechanism for tightening flexible tensioning element 110. Other non-limiting possibilities for tightening flexible tensioning element 110 include a direct pulling by hand or by use of any other dedicated tool. Proximal roller 140 and tensioning element 110 prevent the device from loosening. Tensioning element 110 may be a string, a multi-strand string, beads or other tensioning mechanism. Proximal roller 140 may be replaced by knobs or another drawstring mechanism.

In an alternative implementation, the tensioning element may be anchored at or near the proximal end of the elongated element, and then pass through one or more relatively distal segments, then being doubled-over and passing back to the provide an end to be tightened.

During deployment, the tightener (proximal roller 140) is operated to draw in excess length of flexible tensioning element 110. According to certain embodiment illustrated here, roller 140 may be implemented as a simple bolt which is both rotated and advances backwards relatively to proximal link 134.

Returning now to FIG. 1, second link 130 has an internal hole (along its longitudinal axes) which enables proximal roller 140 to protrude into the body of second link 130 in the straight configuration of the elongated element 100 as proximal roller 140 advanced backwards during the deployment of elongated element 100 and its folding within the patient body. In its closed helix configuration, the proximal roller 140 is pulled back out of second link 130 enabling attachment in between second link 130 and proximal link 134.

FIG. 2 illustrates the multi-level implant 100 in its closed helix configuration, according to embodiments of the present invention. As elongated element 100 assumes a curved configuration, proximal roller 140 is rotated (e.g. is screwed outwardly), thereby winding flexible tensioning element 110 around proximal roller 140, and sequentially attaching the links of elongated element 100 to each other. As shown in FIG. 2, proximal link 134 bottom part is connected to mid link 126 upper part and mid link upper part 126 is connected further to distal link upper part 124. Flexible tensioning element 110 is shown winded around proximal roller 140 and its other end 144 is anchored to distal link 124 through a hole 122 shown in FIG. 1. Flexing tensioning element 110 may be anchored to the proximal link and the flexing tensioning element 110 may be a string threaded through the distal link back to the proximal link.

According to certain embodiments of the present invention, elongated clement 100 may be provided with protrusions and at least part of the elongated element may be provided with complementary recesses, the projections and recesses being configured and deployed such that, when the elongated element assumes the closed helix configuration shown for example in FIG. 2, the protrusions and complementary recesses inter-engage so as to further stabilize and reinforce the closed helix configuration multi-level implant.

As shown in FIG. 2 the flexible tensioning element may be a string 110 and pulling the string may be done by a draw-string roller 140 connected to the proximal link 134 of implant 100, wherein the string 110 may be winded around the proximal roller 140 gradually attaching the distal link 124 bottom part to the proximal portion upper part 134 through mid link 126.

According to embodiments of the present invention, a second locking element may be used for multi-level locking the elongated element 100 in a second position along the element in addition to the distal link to the proximal link locking element shown in FIG. 2.

Although an exemplary embodiment of the tightener 140 is illustrated here as a bolt, other roller arrangements, or tighteners which are implemented as part of a delivery system separate from the implant, may be employed.

In the closed helix configuration, multi-level implant 100 is strongly fastened, stabilized and reinforced by the inter-level locking between distal link 124 and proximal link 134.

As shown in FIG. 2, flexible tensioning element 110 is connected to distal link 124, passing through mid link 126 (potentially through additional links as well), and is wound over proximal roller 140 (which is connected to proximal link 134). It is noted that in other (not shown) embodiments, flexible tensioning element 110 may be anchored to a link other than distal, and may be connected to other link than the proximal one. Optionally, roller 140 may be secured to proximal link 134 using a one directional rotation ratchet arrangement (not shown). Roller 140 may be replaced by any other mechanism preventing tensioning element 110 from loosening.

Tightener 140 may be rolled back in order to loosen tensioning element 110 and to allow multi-level helix implant 100 to be straightened to its initial elongated straightened configuration, for example, for repositioning of the implant, or removal from the body.

FIG. 2 illustrates a closed helix configuration where the proximal link is on top of the multi-level implant and where the distal link is at the bottom of the multi-level implant. However, according to embodiments of the present invention, an opposite helix configuration may be implemented where the distal link is on top of the multi-level implant and where the proximal link is at the bottom of the multi-level implant and both closed helix configurations are in the scope of the present invention.

Furthermore as shown in FIG. 2, multi-level implant 100 may have a helix configuration with 2, 3 or more levels due to the elongated element flexing regions (links for example) that are slightly inclined out-of-plane relative to the plane assumed by an in-plane one level closed loop configuration elongated element. Flexible tensioning element 110 may connect the distal link to the proximal link through multiple helix levels and through multiple mid links.

According to certain embodiments of the present invention, a first tensioning clement may be used for deployment of the implant and a second tensioning element for locking between levels of the multi-level implant. Particularly in such cases, the element employed for locking need not extend to the distal-most or proximal-most segments, and may instead lock between levels at some other position in the helical structure, or only lock between a subset of the levels. Similarly, the locking element may be actuated to lock the helical structure as a separate operation after complete deployment of the structure.

Furthermore, in certain embodiments, the locking element may not be pre-attached to the elongated element prior to deployment, but may instead be separately introduced and deployed after deployment of the helical structure.

Although described herein in a preferred implementation as a tensioning clement, it should be noted that other types of locking elements also fall within the scope of the present invention. Examples include, but are not limited to, various forms of clip, clamp or fastener which engage corresponding features in the elongated element.

According to certain embodiments of the present invention, biocompatible material may be introduced into an inner space of the multi-level implant 100 in its closed helix configuration to achieve various mechanical or therapeutic functions. By way of one non-limiting set of examples, during inter-vertebral fusion, a stabilizing substance, such as bone particles, may be injected into the inner space of the multi-level implant 100 to promote bone growth.

Advantageously, multi-level helix implants described above may be locked, stabilized and reinforced by embodiments of the present invention multi-level locking mechanism.

Another advantage of certain embodiments of the multi-level helix implants described above is that an elongated clement introduced in a straightened configuration through a conduit with relatively small cross section, folds within the body into a multi-level helix configuration with significantly larger cross section and height comparing to the cross section and height of its delivery conduit and where the multi-level helix implants maintain their multi-level helix configuration due to their locking mechanism.

Another advantage of certain embodiments of the multi-level helix implants described above is that the elongated element is provided with protrusions and at least part of the elongated clement is provided with complementary recesses, the projections and recesses being configured and deployed such that, when the elongated element assumes the closed helix configuration the protrusions and complementary recesses inter-engage so as to further stabilize and reinforce the closed helix configuration multi-level implant.

In summary, multi-level helix implants described above may be locked, stabilized and reinforced by embodiments of the present invention multi-level helix implants locking mechanism. After deployment the locked multi-level helix implants assume and maintain a significantly larger cross section and height comparing to the cross section and height of their delivery conduit.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as are commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods are described herein.

All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the patent specification, including definitions, will prevail. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined by the appended claims and includes both combinations and sub-combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description. 

What is claimed is:
 1. An inter-level locking mechanism of a multi-level medical device, comprising: (a) an elongated element having a plurality of flexing regions, wherein said elongated element assumes a straightened configuration for introduction into the body, and wherein said elongated element assumes a closed helix configuration with a first portion of said elongated element coming in overlapping contact with a second portion of said elongated element in said closed helix configuration; and (b) at least one locking element deployable so as to interconnect said first and second portions of said elongated element so as to tighten together said overlapping portions of said elongated element, thereby stabilizing the closed helix configuration.
 2. The locking mechanism of claim 1, wherein said at least one locking element comprises a flexible tensioning element anchored to said first portion of said elongated element and passing directly between levels of said closed helix configuration so as to tighten together said overlapping portions of said elongated element.
 3. The locking mechanism of claim 2, wherein said second portion of said elongated element comes in overlapping contact with a third portion of said elongated element in said closed helix configuration, thereby defining three levels of said closed helix configuration, and wherein said flexible tensioning element additionally engages said third region of said elongated element, thereby tightening together said three levels of said closed helix configuration.
 4. The locking mechanism of claim 1, wherein said second portion of said elongated element comes in overlapping contact with a third portion of said elongated element in said closed helix configuration, thereby defining three levels of said closed helix configuration, and wherein said at least one locking element additionally engages said third region of said elongated element, thereby tightening together said three levels of said closed helix configuration.
 5. The locking mechanism of claim 1, wherein at least part of said elongated element is provided with protrusions and at least part of said elongated element is provided with complementary recesses, said projections and recesses being configured and deployed such that, when said elongated element assumes said closed helix configuration, said protrusions and complementary recesses inter-engage so as to further stabilize and reinforce said closed helix configuration.
 6. The locking mechanism of claim 1, comprising further a second locking element locking said element in a second position along said element in addition to said at least distal portion to said proximal portion locking element.
 7. The locking mechanism of claim 1, wherein said elongated element is formed from a plurality of links interconnected at said plurality of flexing regions.
 8. A method for locking a multi-level medical device within a body, the method comprising the steps of: (a) inserting an elongated element having a plurality of flexing regions, wherein said element assumes a straightened configuration for introduction into the body, and wherein said elongated element assumes a closed helix configuration with a first portion of said elongated element coming in overlapping contact with a second portion of said elongated element in said closed helix configuration when deployed; and (b) deploying a locking element so as to interconnect said first and second portions of said elongated element so as to tighten together said overlapping portions of said elongated element, thereby stabilizing the closed helix configuration.
 9. The method according to claim 8, wherein said locking element comprises a flexible tensioning element anchored at said first portion of said elongated element and passing directly between levels of said closed helix configuration so as to tighten together said overlapping portions of said elongated element.
 10. The method according to claim 8, wherein at least part of an upper or lower overlap surface of said elongated clement is provided with protrusions and at least part of an upper or lower overlap surface of said elongated element is provided with complementary recesses, said projections and recesses being configured and deployed such that, when said locking element is deployed, said projections and recesses are locked in engagement, thereby further stabilizing said closed helix configuration.
 11. The method according to claim 8, further comprising the step of deploying a second locking element locking between levels of said closed helix configuration in an additional region of overlap.
 12. The method according to claim 8, further comprising the step of introducing a stabilizing substance into the inner space of said multi-level closed helix configuration.
 13. The method according to claim 8, further comprising the step of introducing a biocompatible material into the inner space of said multi-level closed helix configuration. 